This weekend offers a variety of rides and events to satisfy any type of bike lover, from leisurely environmental exploration rides to quick-paced road rides to bike classes for kids and adults:

Big Year Bike Ride: Join the Wild Equity Institute for a three-hour ride to learn about, and hopefully see some of, the endangered species right here in San Francisco's Golden Gate National Parks. From the seat of your bicycle, you'll learn about humpback whales, Western snowy plover shorebirds, stellar sea lions, gowen cypress and much more. Bring your bike, lock and binoculars if you have them. (9:30 a.m.-12:30 p.m. Saturday. $5 suggested donation; reservations required. Ride leaves from Bazaar Cafe, 5927 California St. www.wildequity.org/events.)

Ride and lunch with Gary Fisher: Join mountain bike pioneer Gary Fisher on an intimate, fast-paced road ride and luncheon. The ride is limited to 30 people. Learn about the early days of balloon-tire mountain biking on Mount Tamalpais and get an inside look at San Francisco biking from S.F. Bicycle Coalition Executive Director Leah Shahum, who will also be on the ride. Then pedal to Greens Restaurant for a special meal by Greens' head chef, Annie Somerville. (9 a.m. Sunday. $150 tax-deductible donation. Meet at Greens Restaurant, Fort Mason Center. www.sfbike.org/rsvp.)

Sunday Streets: This weekend is the last Sunday Streets of the season. The event heads to the Excelsior for some open-streets fun, filled with music, games and plenty of car-free space to ride your bike. Best yet, the 10th annual Excelsior Art and Music Festival ( www.excelsiorfestival.org) will be happening at the same time, with live music, entertainment, food, crafts, and a kids activities area. (11 a.m.-4 p.m. Sunday. Free. Mission Street, from Silver Avenue to Seneca Street, and Seneca from Mission to San Jose Avenue. www.sundaystreetssf.com.)

Kids Learn to Ride and Family Biking Class: Bring your little one to Sunday Streets and the San Francisco Bicycle Coalition will help teach them to ride a bike at their Freedom From Training Wheels class. And while you're there, get tips and best practices for family bicycling at the 1:30-2:30 p.m. Family Biking class. Bring your child's bike and helmet if you have one; the SF Bicycle Coalition will have a few loaners. (11 a.m.-2 p.m. Sunday. Free. Mission Street at Ruth Street. www.sfbike.org/freedom.)

Bike About Town is presented by the San Francisco Bicycle Coalition, a 12,000-member nonprofit dedicated to creating safer streets and more livable communities by promoting the bicycle for everyday transportation. For more biking resources, go to www.sfbike.org.